DESPERATE (please answer with picture of the graph)
WILL MARK BRAINLIST AND THANKS

Given that (x-3) is a factor of f(x)=x^3+ax^2-x-6, find a and hence the number of real roots or the equation f(x)=0

Atrucker had a load of grain containing 2 tons. she unloaded 1 ton and 1,200 pounds at the warehouse. how much grain does she still have left on the truck?

Me. i can't figure out this question. give an explanation too. .